What is the current situation of foreign reducers? Gear reducer is widely used in all walks of life and is an indispensable mechanical transmission device. At present, reducers are generally large in size and weight, or have large transmission ratio and low mechanical efficiency. In foreign countries, Germany, Denmark and Japan are in the leading position, especially in materials and manufacturing technology, with good reliability and long service life. However, its transmission form is still mainly fixed-axis gear transmission, and the problems of volume and weight have not been well solved. Recently, it was reported that the FA high-precision reducer developed by Sumitomo Heavy Industries and the X-Y reducer developed by Allen-Newton Company in the United States are both advanced gear reducers in terms of transmission principle and structure. Today's reducer is developing towards high power, large transmission ratio, small volume, high mechanical efficiency and long life. Therefore, in addition to continuously improving the material quality and technology level, the transmission principle and structure are also deeply discussed and innovated, and the emergence of translation gear transmission principle is an example. The conjoined structure of reducer and motor is also a form of vigorous development, and products of various structural forms and power models have been produced. At present, the research results of subminiature reducer are not obvious. In medical, bioengineering, robotics and other fields. Micro-engine has been basically developed successfully. The size of molecular engines recently developed by the United States and the Netherlands is in the nanometer range. If it can be supplemented with nano-reductant, it will have broad application prospects.

2. What is the current situation of domestic reducers? Most reducers in China are gear transmission and worm transmission, but there are widespread problems such as small power-to-weight ratio or large transmission ratio and low mechanical efficiency. In addition, there are still many weaknesses in the material and technology level, especially the problem of large reducer is more prominent and its service life is not long. Large reducers (above 500kw) used in China are mostly imported from abroad (such as Denmark and Germany), which consumes a lot of foreign exchange. Reducers produced in 1960s, such as less tooth difference drive, cycloidal pin-wheel drive and harmonic drive, have the advantages of large transmission ratio, small volume and high mechanical efficiency? . However, limited by its transmission theory, it cannot transmit too much power, and the power is generally below 40kw. Because there is no breakthrough in transmission theory, technology level and material quality, the basic requirements of high transmission power, large transmission ratio, small volume, light weight and high mechanical efficiency have not been fundamentally solved. In the early 1990s, a three-ring (gear) reducer appeared in China, which is a kind of reducer with external translational gear transmission. It can realize large transmission ratio and large load transmission capacity. Compared with fixed-axis gear reducer, it has smaller volume, lighter weight, simple structure and higher efficiency. Due to the three-axis parallel structure of the reducer, the power/volume (or weight) ratio is still small. Moreover, its input shaft and output shaft are not on the same axis, which makes it inconvenient to use. The internal translation gear reducer developed by Beijing Institute of Technology not only has the advantages of three-ring reducer, but also has the advantages of large power/weight (or volume) ratio and the same axis of input shaft and output shaft, which is in a leading position in China. A few universities, factories and mines in China have done some research work on some principles of translational gear transmission, published some research papers, and also done some work on using cycloidal gears as translational reducers. 2. Brief introduction to the working principle of translational gear reducer. Translation gear reducer refers to a pair of gear transmission, in which one gear moves in parallel under the drive of translation generator, and the meshing of tooth profile drives the other gear to rotate and decelerate, thus realizing the function of deceleration transmission. The translation generator can adopt parallelogram mechanism, sine mechanism or cross slider mechanism. In this paper, parallelogram mechanism is used as translation generator. The translation generator can be a virtual parallelogram mechanism or a solid parallelogram mechanism. Translational gear mechanism with practical value is a kind of internal meshing gear mechanism, so it can be divided into two cases: internal gear translation and external gear translation. External translation gear reduction mechanism, internal gear translation, driving external gear, deceleration rotation output. This mechanism is also called three-ring (gear) reducer. Because the internal gear moves in translation, and the centers of the two cranks are located outside the gear ring of the internal gear, the problems of compact size and large volume cannot be solved. ? The inner translation gear decelerates, and its outer gear translates to drive the inner gear to decelerate and rotate. Because the external gear translates, the centers of the two cranks can be arranged in the gear ring of the external gear, which greatly reduces the overall size of the mechanism. Because of its high transmission efficiency, small size and coaxial input and output, the internal translation gear mechanism has broad application prospects. ? Three. What are the technical characteristics and key technologies of this project? 1. Technical characteristics of this project. Compared with the existing gear reducers at home and abroad, this new type of "internal translational gear reducer" has the following characteristics: (1) The transmission ratio ranges from I= 10, up to several thousand. If it is made into a reducer with large transmission ratio, it will show the advantages of this reducer. (2) Wide power transmission range: it can be integrated with the motor. (3) simple structure, small volume and light weight. It is about 1/3 less than the existing gear reducer. (4) High mechanical efficiency. The meshing efficiency is more than 95%, and the overall efficiency is more than 85%. The efficiency of the reducer will not decrease with the increase of transmission ratio, which is beyond the reach of many other reducers. (5) The input shaft and output shaft of the reducer are on the same axis. See table 1 for the performance comparison between this reducer and other reducers. Due to the lack of data, the power/weight ratio of each reducer listed in the table is the best. ? Table 1? Comparative power (kw) and deceleration specific mass (kg) of various types of reducers QI-450? 93 3 1.5 1820 ZSY-250？ 95 31.5 540 NGW-92 88.1.31.5 577 sew (Germany)? 90 28.6 1 1300 NP- 100？ 100 30 400 note: NP- 100 is an internal translation gear reducer, and the mass of SEW reducer includes motor. 2. What are the key technologies of this project? As can be seen from Figure 2, the "internal translational gear reducer" consists of an internal gear Z2, an external gear Z 1 and a parallelogram mechanism. Its transmission principle is: the motor inputs rotary motion, the external gear moves in parallel, the trajectory of its center is a circle, and the internal gear engaged with it rotates around a fixed shaft. Because the external gear moves in parallel, it is called a translational gear mechanism. If the parallel movement of gears needs the help of auxiliary mechanisms, you can use (6~ 12 pairs) pins and rollers as virtual auxiliary translation mechanisms, or you can use eccentric shafts as solid auxiliary translation mechanisms. The key technology and technology of internal translation gear reducer are the calculation of parallelogram component size, the required machining accuracy and the selection of main parameters of gear teeth. These factors will affect the transmission capacity and transmission quality. Generally speaking, the parts of this reducer require high precision, which will determine the overall transmission quality of the reducer. 3. Overview of the Project This project has obtained a patent for utility model in China with the patent number ZL95227767.0? . ? 1995 produced the first prototype (power 2.5kW, transmission ratio I=32), and cooperated with some factories and mines to design the following reducers with different power and transmission ratio. (1) electric sliding door reducer, power 550W, transmission ratio I=26, integrated with motor. (2) Reducer for mixer, power 370W, transmission ratio I= 17. (3) There are two kinds of military reducer, one is a two-stage transmission reducer with power of 370W and transmission ratio I = 23.5 and the other is 370W and transmission ratio I= 103. (4) The power of reducer of large ladle turret in steel plant is 7.5kw, and the transmission ratio I=64. (5) Mill roll reducer with power of 7.5kw and transmission I= 1 1. On the basis of this patent, a new super-large reducer has been developed, and the power can reach 1000kw. At present, a super-small (millimeter level) micro reducer is being developed.